Ball Screws - Load lock

The Load lock safety feature prevents free-fall of a vertical ball nut in the case of a loss of ball bearings.  This is an integral safety feature to protect people and equipment. During normal operation, there is no impact to ball nut performance. 

The load lock feature is a coiled wire that fits in the ball groove of an unused portion of the nut.  The screw and the wire have a gap and will only touch if the bearings in the nut are lost.  Upon catastrophic ball loss, the free space will be taken up by the load lock.  This essentially converts the ball screw into a lead screw.  The load lock can also be accomplished by machining an inverted ball form into the unused portion of the ball nut.